Greece has suspended the operation of hundreds of fan clubs associated with soccer teams in a bid to combat hooligans using them as cover.

The ban, which will apply until the end of July, was announced on Monday as part of a series of measures designed to address violence at sports events following the brutal killing of a 19-year-old soccer fan in the northern port city of Thessaloniki on February 1 in an attack connected to soccer fan rivalry.

Authorities had until Sunday raided 575 fan clubs across Greece, Citizen Protection Minister Takis Theodorikakos told a press briefing. They also issued a permanent ban on 67 clubs and made 17 arrests, he said.

“It is time that we killed the Lernaean Hydra of violence and hooliganism,” Theodorikakos said.